JP5474930B2 - Cover film - Google Patents

Description

  The present invention relates to a cover film for carrier tape used for packaging electronic components.

  Along with the downsizing of electronic devices, the electronic components used are also becoming smaller and higher performance, and in the assembly process of electronic devices, electronic components are automatically mounted on a printed circuit board. In general, electronic components for surface mounting are stored in a carrier tape in which pockets for storing electronic components are continuously embossed, and a cover film is placed on the top surface of the carrier tape as a cover material and continuous with a seal bar. Stored and transported in the form of an electronic component package obtained by heat sealing. As the cover film, a base material made of a biaxially stretched polyester film and a sealant layer made of a thermoplastic resin are laminated.

  When mounting electronic components in the manufacture of electronic devices, etc., the cover film is peeled off from the carrier tape by an automatic peeling device, and the electronic components stored in the carrier tape are taken out by the pickup device and surface-mounted on the electronic circuit board. The Therefore, it is particularly important for the cover film that the peel strength with the carrier tape is stable within an appropriate range. If the peel strength is too strong, the cover film may be cut off at the time of peeling. Conversely, if the peel strength is too weak, the cover film may be peeled off from the carrier tape at the time of storage / transfer, and the electronic components as contents may fall off. In particular, with the rapid increase in mounting speed, the peeling speed of the cover film is also extremely high, 0.1 seconds or less / tact, and a large stress is applied to the cover film during peeling. As a result, there arises a problem called “film cut” in which the cover film is cut.

  The peel strength at the time of peeling the cover film from the carrier tape is JIS C0806-3, when the peel speed is 300 mm / min, the carrier tape of 8 mm width is 0.1 to 1.0 N, and the carrier width is 12 mm to 56 mm. It is specified as 0.1 to 1.3 N on the tape. However, in the actual electronic component mounting process, the peeling speed is faster than 300 mm per minute, and particularly when storing a large connector part, it is often sealed with a peeling strength close to the upper limit. When the cover film is peeled off, the film breaks easily.

  As a countermeasure against film breakage, a method has been proposed in which an intermediate layer having excellent impact resistance and tear propagation resistance, such as polypropylene, nylon and polyurethane, is provided between a base material such as a biaxially stretched polyester film and a sealant layer. (See Patent Documents 1 to 3). On the other hand, a metallocene linear low density polyethylene (m-LLDPE) having a specific gravity is used as the intermediate layer, and the adhesive layer between the intermediate layer and the base material layer has a low Young's modulus. A method for preventing stress propagation to the layer has been proposed (see Patent Document 4). In addition, for the purpose of obtaining a cover film having a low sealing temperature dependency and change with time of the peel strength and having a stable sealing property, a styrene-butadiene-styrene block copolymer is mixed with polyethylene or polypropylene as a sealant resin composition. Has been proposed (see Patent Document 5). However, even with these methods, it has been difficult to sufficiently suppress film breakage at high speed peeling such as 100 m / min.

  Furthermore, a cover film has been proposed in which layers made of styrene-based hydrocarbon resin are coextruded to improve the adhesion between the layers (see Patent Document 6). However, even with this method, the stability of the peel strength after heat sealing was insufficient.

In high-speed peeling, since static electricity is generated by peeling, it is required to suppress static electricity failure at the time of peeling.
As a technique for reducing the generation of static electricity due to peeling, a technique of kneading conductive carbon particles, conductive powder such as metal oxide, and metal fine particles in a sealant layer of a cover film is performed (see, for example, Patent Document 1). However, since metal oxides and the like are relatively expensive, it is easy to increase the cost, and it is not easy to uniformly disperse the metal oxides and the like in the sealant layer, and the dispersion strength varies due to poor dispersion. There is.

  In addition, it has been proposed to disperse a surfactant in a sealant layer (see Patent Document 7), but when an electronic component package body in which a cover film is heat-sealed on a carrier tape is stored for several days in a hot and humid environment, When the surfactant migrates to the surface of the sealant layer, the peel strength is lowered and the cover film may be peeled off.

  Furthermore, a method has been proposed in which conductive fine particles or the like are not mixed in the sealant layer, and a charge transfer layer is provided between the base material layer and the sealant layer to prevent static electricity from being charged on the surface of the sealant layer (patent) Reference 8). The method of heat-sealing with a sealant layer that does not contain foreign substances such as conductive fine particles is intended to stabilize the peel strength, and has a great effect in that respect. However, due to miniaturization of electronic components and the like, a higher level of suppression of static electricity generated on the surface of the sealant layer is required, and the required performance may not be satisfied.

In addition to the above characteristics, the cover film may also require high transparency so that an electronic component that is a stored item can be easily identified. For example, in the inspection of electronic parts such as ICs, a method of discriminating defects such as deformation of IC pins by taking a picture with a CCD camera from a cover film and analyzing the image is performed. A cover film having properties is required. In order to efficiently perform such identification, a cover film having a haze (haze value) of 50% or less and a total light transmittance of 75% or more is required.
Japanese Patent No. 3241220 Japanese Patent Laid-Open No. 10-250020 JP 2000-327024 A JP 2006-327624 A JP-A-8-324676 JP 2007-90725 A JP 2004-51106 A Japanese Patent Laid-Open No. 2005-178073

The present invention provides a cover film that hardly causes “film breakage” even during high-speed peeling, and is excellent in heat sealability, stability of peel strength, and transparency.
Furthermore, the present invention provides a cover film in which the occurrence of static electricity damage due to peeling is suppressed in addition to the above characteristics.
The present invention also provides an electronic component package that is particularly suitable for high-speed mounting of electronic components.

（式中、Ａは酸素原子又はイミノ基を示し、Ｒ_１は水素原子又はメチル基を示し、Ｒ_２、Ｒ_３及びＲ_４はそれぞれ同一でも異なっていてもよい炭素原子数１〜１８のアルキル基を示し、Ｒ_５は炭素原子数１〜４のアルキレン基を示し、Ｘ⁻はアニオンを示し、かつ、ｍは１〜５０００の範囲の整数を示す）
で示される第４級アンモニウム塩を側鎖に持つカチオン性高分子型帯電防止剤をアクリル系樹脂中に分散させた樹脂組成物からなる帯電防止層を有する（１）〜（６）記載のカバーフィルム。
（８）帯電防止層を構成する樹脂組成物におけるカチオン性高分子型帯電防止剤とアクリル系樹脂との割合が、カチオン性高分子型帯電防止剤２０〜６０質量％、アクリル系樹脂４０〜８０質量％である（７）記載のカバーフィルム。
（９）帯電防止層が有機系微粒子または無機系微粒子を１０〜５０質量％含む（７）または（８）に記載のカバーフィルム。
（１０）上記（１）〜（９）のいずれかに記載のカバーフィルムを、電子部品を収納したエンボスキャリアテープにヒートシールした電子部品包装体。The present invention employs the following means in order to solve the above problems. That is, according to the present invention, the following cover film or electronic component package is provided.
(1) A base material layer, an intermediate layer composed of a resin composition containing 50% by mass or more of a metallocene linear low density polyethylene resin having a density of 0.900 to 0.940 × 10 ³ kg / m ³ , and an olefin component A cover film that is heat-sealed to a carrier tape that houses an electronic component, comprising a sealant layer made of an ethylene-based copolymer resin containing 50 to 85% by mass.
(2) The cover film according to (1), wherein the olefin component of the ethylene copolymer resin constituting the sealant layer is selected from the group consisting of ethylene, propylene, butene, butadiene, and isoprene.
(3) The ethylene copolymer resin constituting the sealant layer is an ethylene-propylene random copolymer resin, an ethylene-1-butene random copolymer resin, an ethylene-vinyl acetate copolymer resin, an ethylene-acrylic acid random copolymer resin, Ethylene-acrylic acid ester random copolymer resin, ethylene-methacrylic acid random copolymer resin, ethylene-methacrylic acid ester random copolymer resin, ethylene-styrene random copolymer resin, hydrogenated product of styrene-butadiene block copolymer resin, styrene The hydrogenated product of isoprene block copolymer resin, the hydrogenated product of styrene-butadiene-styrene block copolymer resin, and the hydrogenated product of styrene-isoprene-styrene copolymer resin as described in (2) Cover film.
(4) The ethylene copolymer resin constituting the sealant layer is an ethylene-acrylate random copolymer resin, an ethylene-methacrylate random copolymer resin, a hydrogenated product of a styrene-butadiene-styrene block copolymer, and The cover film according to (3), which is selected from the group consisting of hydrogenated styrene-isoprene-styrene block copolymers.
(5) The cover film according to (1) to (4), wherein the sealant layer contains 5 to 30% by mass of organic fine particles or inorganic fine particles.

(6) The cover film according to any one of (1) to (5), wherein the base material layer is made of a biaxially stretched polyethylene terephthalate or a resin composition containing biaxially stretched polyethylene terephthalate.
(7) On the sealant layer side surface, the following general formula:

(In the formula, A represents an oxygen atom or an imino group, R ₁ represents a hydrogen atom or a methyl group, and R ₂ , R ₃ and R ₄ may be the same or different, each having 1 to 18 carbon atoms. R ₅ represents an alkylene group having 1 to 4 carbon atoms, X ⁻ represents an anion, and m represents an integer in the range of 1 to 5000)
The cover according to any one of (1) to (6), comprising an antistatic layer comprising a resin composition in which a cationic polymer type antistatic agent having a quaternary ammonium salt represented by formula (1) is dispersed in an acrylic resin. the film.
(8) The ratio of the cationic polymer type antistatic agent to the acrylic resin in the resin composition constituting the antistatic layer is 20 to 60% by mass of the cationic polymer type antistatic agent, and the acrylic resin is 40 to 80%. The cover film according to (7), which is mass%.
(9) The cover film according to (7) or (8), wherein the antistatic layer contains 10 to 50% by mass of organic fine particles or inorganic fine particles.
(10) An electronic component package in which the cover film according to any one of (1) to (9) is heat-sealed on an embossed carrier tape containing electronic components.

  The cover film of the present invention can sufficiently suppress the occurrence of “film breakage” during high-speed peeling from the carrier tape, and is excellent in heat sealability, stability of peel strength, and transparency. Furthermore, in addition to the above characteristics, the cover film of the present invention can also suppress electrostatic damage during peeling. Moreover, the electronic component package of the present invention obtained using such a cover film is particularly suitable for high-speed mounting of electronic components.

It is a schematic sectional drawing of the cover film concerning one Embodiment of this invention which an intermediate | middle layer consists of two layers. It is a schematic sectional drawing of the cover film concerning one Embodiment of this invention which an intermediate | middle layer consists of one layer. It is a schematic sectional drawing of the cover film concerning one Embodiment of this invention which has an antistatic layer in the sealant layer side surface. It is the schematic showing the test method of the film breakability of a cover film.

DESCRIPTION OF SYMBOLS 1 Cover film 2 Base material layer 3 Anchor coat layer 4 Intermediate layer 41 First intermediate layer 42 Second intermediate layer 5 Sealant layer 6 Antistatic layer 101 Wall 102 Double-sided adhesive tape 103 Carrier tape 104 Clip 105 String 106 Weight

Hereinafter, modes for carrying out the present invention will be described.
The cover film according to this embodiment has at least a base material layer, an intermediate layer, and a sealant layer.

[Base material layer]
The base material layer is made of a biaxially stretched polyethylene terephthalate or a resin composition mainly composed of biaxially stretched polyethylene terephthalate. As the biaxially stretched polyethylene terephthalate, a commercially available one can be used, and one obtained by applying or kneading an antistatic agent for antistatic treatment, or one subjected to corona treatment or easy adhesion treatment. It can also be used. If the base material layer is too thin, it is easy to cause “film breakage” when the cover film is peeled off. On the other hand, if the base layer is too thick, sufficient heat is not transferred to the sealant layer when the cover film is heat-sealed to the carrier tape. Since it becomes difficult to obtain a film having a thickness of usually 12 to 25 μm, it can be suitably used.

[Middle layer]
The intermediate layer is located between the base material layer and the sealant layer, and may be composed of a single layer or may be composed of two or more layers.
The intermediate layer is made of a resin composition mainly composed of linear low density polyethylene (LLDPE) that has flexibility and high rigidity and has high tear strength at room temperature. There are two types of LLDPE, one polymerized with a Ziegler type catalyst (Zigler type LLDPE) and one polymerized with a metallocene catalyst (m-LLDPE), but m-LLDPE has a low crystallization because the molecular weight distribution can be controlled narrowly. It is possible to suppress the generation of adhesiveness and the unnecessarily lowering of the melting point, and in particular from the viewpoint of high tear strength, it is preferable to use m-LLDPE as the LLDPE constituting the intermediate layer.

  m-LLDPE is an olefin having 3 or more carbon atoms as a comonomer, preferably a linear α-olefin having 3 to 18 carbon atoms, a branched α-olefin, or an α-olefin substituted with an aromatic nucleus, and ethylene. It is a copolymer resin. Examples of the linear α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and the like can be mentioned. Examples of the branched α-olefin include 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene, 2,2,4- And trimethyl-1-pentene. Moreover, styrene etc. are mentioned as an alpha olefin substituted by the aromatic nucleus. These comonomers can be copolymerized with ethylene singly or in combination of two or more. Further, polyenes such as butadiene, isoprene, 1,4-hexadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene may be copolymerized. The α-olefin content in the copolymer resin is preferably 1 to 20 mol%, more preferably 10 to 15 mol%, from the viewpoint of obtaining an improvement effect against film breakage.

m-LLDPE is particularly preferably 50% by mass or more, more preferably 70% by mass or more, based on the resin composition constituting the intermediate layer. m-LLDPE preferably has a density in the range of 0.900 to 0.940 (× 10 ³ kg / m ³ ). m-LLDPE has a fluidity of 0.1 to 8.0 g / 10 min when measured under the condition of 190 ° C. × 5 kg load in accordance with JISK-7112. This is preferable in that stable peel strength is easily obtained when heat sealing.

On the other hand, the intermediate layer can contain low-density polyethylene in a range of less than 50% by mass with respect to the resin composition constituting the intermediate layer. The low density polyethylene preferably has a density in the range of 0.910 to 0.929 (× 10 ³ kg / m ³ ). By containing low-density polyethylene, the film forming property is further improved.

  The thickness of the intermediate layer is generally 5 to 50 μm, preferably 10 to 30 μm. If the thickness of the intermediate layer is less than 5 μm, the adhesive strength between the base material layer and the intermediate layer may be insufficient. If the thickness exceeds 50 μm, the total thickness of the cover film increases, and the cover film is heat-sealed on a carrier tape. In this case, heat cannot be sufficiently transmitted to the sealant layer, and it may be difficult to obtain sufficient peel strength when the cover film is heat sealed to the carrier tape.

[Sealant layer]
The sealant layer has a ratio of 50% to 85% by weight of the olefin component and 15% to 50% by weight of the other comonomer component, more preferably 70% to 80% by weight of the olefin component and 20% of the other comonomer component. It consists of the resin composition containing the ethylene-type copolymer resin contained in the ratio of the mass%-30 mass%.
In the present invention, the “olefin component” refers to monoolefin components such as ethylene, propylene and butene, and diolefin components such as butadiene and isoprene. In the present invention, the “ethylene copolymer resin” refers to a copolymer resin in which the main component in the olefin unit is an ethylene unit when the copolymer resin is classified into monomer units. For example, in the case of a hydrogenated product of a styrene-butadiene block copolymer resin, a block portion where 1,4-butadiene is polymerized is an ethylene copolymer resin in which an ethylene unit is formed by hydrogenation. When the ratio of the olefin component in the ethylene copolymer resin is less than 50% by mass, the heat-melt elongation of the ethylene copolymer resin is small, and molding may be difficult. On the other hand, when the ratio of the olefin component exceeds 85% by mass, it may be difficult to obtain sufficient peel strength when the cover film is heat-sealed on the carrier tape.

Examples of the ethylene copolymer resin containing a monoolefin component include ethylene-propylene random copolymer resin, ethylene-1-butene random copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid random copolymer resin, Examples thereof include ethylene-acrylic acid ester random copolymer resins, ethylene-methacrylic acid random copolymer resins, ethylene-methacrylic acid ester random copolymer resins, and ethylene-styrene random copolymer resins. Moreover, as the ethylene copolymer resin containing a diolefin component, a hydrogenated product of a block copolymer resin of an aromatic vinyl compound and a conjugated diene compound can be suitably used. Examples include hydrogenated styrene-butadiene block copolymer resins, hydrogenated styrene-isoprene block copolymer resins, hydrogenated styrene-butadiene-styrene block copolymer resins, and styrene-isoprene-styrene copolymer resins. Examples include hydrogenated substances.
Among them, ethylene-acrylic acid ester random copolymer resin, ethylene-methacrylic acid ester random copolymer resin, hydrogenated product of styrene-butadiene-styrene block copolymer, and hydrogenated product of styrene-isoprene-styrene block copolymer are , Polystyrene, polycarbonate, polyethylene terephthalate, etc., which are excellent in heat sealability with a carrier tape, and are less likely to cause film breakage.

  In the resin composition constituting the sealant layer, in addition to the ethylene copolymer resin, resins such as polyethylene, ethylene-1-butene copolymer, polystyrene, polyacrylic acid ester, and polypropylene are contained in a range of less than 50% by mass. Can be added.

  In order to prevent blocking when the cover film is wound on the sealant layer, organic particles such as spherical or crushed acrylic particles, styrene particles, silicone particles, talc particles, silica particles, alumina particles Inorganic particles such as mica particles, calcium carbonate, and magnesium carbonate can be added. In particular, acrylic particles and silica particles can be used more favorably because there is little decrease in transparency when added. The maximum frequency diameter obtained from the weight distribution curve of the particles is preferably 1 to 20 μm, more preferably 1 to 15 μm. If the maximum frequency diameter is less than 1 μm, the antiblocking effect due to the addition of particles may not be sufficiently exhibited. On the other hand, when it exceeds 20 μm, the effect of blocking prevention is improved, but a large amount of addition is necessary to prevent blocking, which increases the cost, and the surface roughness of the sealant layer of the cover film is visible. May cause the appearance of the cover film to be impaired. The addition amount of the particles is preferably 5 to 30% by mass, more preferably 10 to 20% by mass in the resin composition constituting the sealant layer. When the addition amount is within this range, a good balance can be achieved in any of transparency, heat sealability, and blocking prevention effect.

  The thickness of the sealant layer is preferably 5 μm to 40 μm, more preferably 7 to 20 μm. When the thickness of the sealant layer is less than 5 μm, sufficient peel strength cannot be obtained when heat-sealing with the carrier tape, and the film may be cut. If it exceeds 40 μm, not only will the cost be increased, but the transparency tends to decrease.

[Method for producing cover film having a layer structure of base material layer / intermediate layer / sealant layer]
Hereinafter, a method for producing a cover film having a layer structure of base material layer / intermediate layer / sealant layer will be described with reference to FIGS.

The method of laminating the base material layer 2, the intermediate layer 4 (or 41 and 42) and the sealant layer 5 is not particularly limited, and a general method can be used.
For example, in the case of the cover film 1 shown in FIG. 2, the components constituting the sealant layer 5 are blended using a mixer such as a Henschel mixer, a tumbler mixer, or a mazeller, and this is directly formed into a film by an extruder, or Once the pellets are obtained by kneading and extruding with a single or biaxial extruder, the pellets are further extruded with an extruder to form a film. As a method for forming a film, any method such as an inflation method, a T-die method, a casting method, or a calendar method may be used, but an inflation method or a T-die method is usually used.

Next, a resin composition mainly composed of molten m-LLDPE constituting the intermediate layer 4 is supplied between the film of the sealant layer 5 and the separately prepared film of the base material layer 2 by an extrusion laminating method. Thereby, the cover film 1 which has the layer structure of the base material layer 2, the intermediate | middle layer 4, and the sealant layer 5 can be manufactured.
For example, a T-die can be used as a die for extruding and supplying a resin composition mainly composed of melted m-LLDPE according to the extrusion lamination method. Further, a deckle for adjusting the film width may be provided. It is preferable to apply an anchor coating agent (illustrated as anchor coating layer 3) such as a urethane resin as an adhesion aid to the surface of the base material layer 2 on the side in contact with the intermediate layer 4. As the coater for applying the anchor coating agent to the base material layer 2, a commonly used one such as a roll coater, a gravure coater, a reverse roll coater, a bar coater or a die coater can be used.

  Alternatively, the resin composition constituting the intermediate layer 4 and the resin composition constituting the sealant layer 5 are melt-kneaded using separate single-screw or twin-screw extruders, and both are fed into a feed block or multi-manifold die. And then co-extrusion from a T die to form a two-layer film in which the intermediate layer 4 and the sealant layer 5 are laminated, and then the intermediate layer 4 side of the two-layer film The base material layer 2 may be dry laminated on the surface via an anchor coat agent. A general laminator can be used as a laminated film manufacturing machine according to the dry laminating method.

  Moreover, like the cover film 1 shown in FIG. 1, the resin composition which comprises the 1st intermediate | middle layer 41, and the resin composition which comprises the sealant layer 5 are respectively used for another single-screw or biaxial extruder. After melt-kneading and laminating and integrating the two through a feed block and a multi-manifold die, a two-layer film in which the first intermediate layer 41 and the sealant layer 5 are laminated is manufactured by co-extrusion from the T die. Then, a resin composition mainly composed of molten m-LLDPE constituting the second intermediate layer 42 is formed between the surface of the two-layer film on the first intermediate layer 41 side and the base material layer 2. By supplying by an extrusion laminating method, the cover film 1 having an intermediate layer composed of a plurality of layers can be produced. Even in this case, it is preferable to apply an anchor coat agent (illustrated as the anchor coat layer 3) such as urethane resin to the surface of the base material layer 2 that is in contact with the second intermediate layer 42.

  Moreover, it is preferable to carry out the antistatic process to the base material layer 2 as needed. As an antistatic agent used for the base layer 2, for example, an anionic, cationic, nonionic, betaine type surfactant type antistatic agent, a polymer type antistatic agent, a conductive agent or the like is used. Can do. These antistatic agents can be applied to the base layer 2 by a roll coater, a lip coater, a spray or the like using a gravure roll. Further, in order to uniformly apply these antistatic agents, it is preferable to subject the film surface of the base layer 2 to corona discharge treatment or ozone treatment before performing antistatic treatment, and in particular, to perform corona discharge treatment. preferable.

[Antistatic layer]
The cover film having the above-mentioned base material layer, intermediate layer, and sealant layer is less likely to cause “film breakage” even during high-speed peeling, and is excellent in heat sealability, stability of peel strength, and transparency. In order to further suppress the occurrence of static electricity damage due to peeling without impairing the characteristics, it is preferable to form an antistatic layer on the surface of the sealant layer.

For the antistatic layer, it is preferable to use a cationic polymer type antistatic agent having a repeating unit derived from a monomer represented by the following general formula and having a quaternary ammonium salt in the side chain.

In the above formula (1), A represents an oxygen atom or an imino group, R ₁ represents a hydrogen atom or a methyl group, and R ₂ , R _3, and R ₄ may be the same or different, 18 represents an alkyl group, R ₅ represents an alkylene group having 1 to 4 carbon atoms, X ⁻ represents an anion, and m represents an integer in the range of 1 to 5000.

X ^- is _{^{the, [B (OCH 3) 4}} ] -, [B (OC 2 H 5) 4] -, [B (OC 3 H 7) 4] -, [B (OC 6 H 5) 4] - Borate ester anions such as I ⁻ and Cl ^{− and the} like; H ₂ PO ₄ ⁻ , BF ₄ ⁻ , CH ₃ SO ₄ ⁻ , C ₂ H ₅ SO ₄ ⁻ , CH ₃ COO ⁻ , NO ₃ ⁻ , SbF ₆ ⁻ , PF ₆ ^{— and the} like can be mentioned, and each structural unit may be the same or different. In particular, halogen anions, CH ₃ SO ₄ ⁻ , C ₂ H ₅ SO ₄ ^{— and the} like are excellent in antistatic properties and can be suitably used.

  As the cationic polymer type antistatic agent having the above-described structure, known ones can be used, and in particular, an aqueous solution or an aqueous emulsion can be preferably used. Commercially available products can be used. Specific products include, for example, Saftmer ST1000, Saftmer ST-2000 (manufactured by Mitsubishi Chemical Corporation), ASA-29CP, ASA-31CP (Takamatsu Yushi Co., Ltd.). Manufactured), Bondip PA, Bondip PM (manufactured by Konishi), SF antistatic coating agent M-2 (manufactured by DIC), and the like.

  The antistatic layer is composed of a cationic polymer antistatic agent dispersed in an acrylic resin. The proportion is preferably 20 to 60% by weight of a cationic polymer type antistatic agent and 40 to 80% by weight of an acrylic resin, more preferably 30 to 50% by weight of a cationic polymer type antistatic agent, and an acrylic type. It consists of resin 50-70 mass%. When the cationic polymer type antistatic agent is less than 20% by mass, it is difficult to obtain sufficient antistatic properties, and when it exceeds 60% by mass, the cover film is heat-sealed on a carrier tape. It may be difficult to obtain sufficient peel strength.

  The acrylic resin used for the antistatic layer is a copolymer resin obtained by polymerizing a monomer of an aliphatic unsaturated carboxylic acid and / or an aliphatic unsaturated carboxylic acid alkyl ester, and an ethylene-aliphatic unsaturated carboxylic acid. It is a copolymer resin of an acid and / or an aliphatic unsaturated carboxylic acid alkyl ester. Examples of the aliphatic unsaturated carboxylic acid and / or the aliphatic unsaturated carboxylic acid alkyl ester include acrylic acid or methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, hexyl acrylate, acrylic acid 2- Use one or more ester derivatives of C1-C12 alcohols such as ethylhexyl and acrylic acid, and also methacrylic acid, or ester derivatives of C1-C12 alcohols such as methyl methacrylate and ethyl methacrylate and methacrylic acid. Can do. Among them, aliphatic unsaturated carboxylic acid esters are preferably used, and n-butyl methacrylate, ethyl methacrylate, and methyl methacrylate are particularly preferable because of excellent water resistance. These aliphatic unsaturated carboxylic acids and / or carboxylic acid alkyl esters may be used alone or in combination of two or more.

  In the acrylic resin, additives such as a dispersion stabilizer, a lubricant and an antioxidant can be further blended as necessary. Further, the acrylic resin may be crosslinked by adding a crosslinking agent. For the purpose of preventing blocking, organic particles such as spherical or crushed acrylic particles, styrene particles, and silicone particles, and inorganic particles such as talc particles, silica particles, alumina particles, mica particles, calcium carbonate, and magnesium carbonate Particles can be added. In particular, silica particles and alumina particles can be used more suitably because of little decrease in transparency when added. The amount of these particles added is preferably 10 to 50% by mass, more preferably 15 to 35% by mass in the resin composition constituting the antistatic layer. If the addition amount is within this range, a balance can be achieved in any of transparency, heat sealability and antiblocking effect.

[Method for producing cover film having a layer structure of base layer / intermediate layer / sealant layer / antistatic layer]
Hereinafter, a method for producing a cover film having a layer structure of base material layer / intermediate layer / sealant layer / antistatic layer will be described with reference to FIG.
In order to produce the cover film 1 having a layer structure comprising the base material layer 2 / intermediate layer 4 / sealant layer 5 / antistatic layer 6, typically, the base material layer 2 / intermediate layer 4 / sealant is produced by the method described above. A laminated film composed of the layer 5 is manufactured, and then the antistatic layer 6 is formed on the surface of the sealant layer 5 side.

  As a prescription for forming the antistatic layer 6 on the surface of the laminated film on the sealant layer 5 side, a general method can be used. For example, the antistatic layer 6 can be formed by directly applying an aqueous solution or water-based emulsion containing the resin composition constituting the antistatic layer 6 to the surface of the sealant layer 5 and drying it. The coating method can be carried out by a known technique such as a gravure coater, reverse coater, kiss coater, air knife coater, Mayer bar coater, dip coater and the like. In this case, before coating, the surface of the sealant layer 5 is preferably subjected to corona treatment or ozone treatment, and particularly preferably corona treatment.

  The thickness of the antistatic layer 6 after drying is preferably in the range of 0.1 to 1 μm, particularly 0.1 to 0.4 μm. If the thickness of the antistatic layer 6 is less than 0.1 μm, sufficient surface resistivity may not be obtained. If the thickness exceeds 1 μm, not only is it likely to increase the cost, but the cover film is heated on the carrier tape. When sealed, it may be difficult to obtain a sufficient peel strength.

[Cover film]
The obtained cover film can be used as a cover material for a carrier tape that is a container for electronic components.
The carrier tape is a belt-like object having a width of about 8 mm to 100 mm in which depressions for storing electronic components are formed at predetermined intervals. The carrier tape is not particularly limited, and a commercially available tape can be used. The material of the carrier tape is not particularly limited, and for example, paper, polystyrene, polyester, polypropylene, polycarbonate, polyacrylonitrile, polyvinyl chloride, acrylonitrile / butadiene / styrene copolymer resin, and the like can be used. Carrier tapes are those imparted with conductivity by kneading carbon black or carbon nanotubes into the resin, those imparted with antistatic properties by kneading antistatic agents or conductive fillers, or surfactants on the surface of the carrier tape. An antistatic agent imparted with antistatic properties by applying a coating liquid in which a conductive material such as an antistatic agent, polypyrrole, or polythiophene is dispersed in an organic binder such as acrylic can be used.

[Electronic parts packaging]
An electronic component package is obtained by storing electronic components etc. in the electronic component storage part of the carrier tape, covering the cover film as a lid, and continuously heat-sealing both edges along the longitudinal direction of the cover film. It is done. The electronic component package is usually stored and transported in a state of being wound on a reel.

  When mounting an electronic component housed in an electronic component package on an electronic circuit board or the like, the carrier tape is fed at a high speed from the carrier tape while feeding the carrier tape through a hole for feeding provided in the longitudinal edge of the carrier tape. The cover tape is intermittently peeled off, and the electronic components are taken out one by one while confirming the presence, orientation, and position of the electronic components etc. with a pickup device.

  EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not limited to the content of description of this Example.

  Tables 1, 2 and 3 show the abbreviations, trade names and / or characteristics of materials used for the intermediate layer, sealant layer and antistatic layer. In the tables described herein, the abbreviations shown here are used for the sake of brevity.

m-LLDPE：メタロセン直鎖状低密度ポリエチレン
HIPS：ハイインパクトポリスチレン
LDPE：低密度ポリエチレン
注(*1) ＪＩＳＫ−７１１２準拠、 １９０℃×５ｋｇ荷重での測定値

m-LLDPE: Metallocene linear low density polyethylene
HIPS: High impact polystyrene
LDPE: Low density polyethylene Note (* 1) Measured at 190 ° C x 5 kg load, JISK-7112 compliant

[Cover film having a layer structure of base layer / intermediate layer / sealant layer]
Example 1
100 parts by mass of styrene-butadiene-styrene triblock copolymer hydrogenated product “Tuftec H1041” (manufactured by Asahi Kasei Chemicals), 50% by mass of low-density polyethylene, 45% by mass of silica, and 5% by mass of talc Anti-blocking agent masterbatch "PEX ABT-16" (manufactured by Tokyo Ink Co., Ltd.) (hereinafter referred to as "anti-blocking agent 1") 25 parts by mass with a tumbler, and a uniaxial with a diameter of 40 mm The mixture was kneaded at 200 ° C. using an extruder to obtain a resin composition for a sealant layer at a line speed of 20 m / min.
The resin composition for the sealant layer and the m-LLDPE “Evolue SP3010” (manufactured by Prime Polymer Co., Ltd.) for the first intermediate layer are extruded from individual single-screw extruders and laminated and extruded with a multi-manifold T-die. Thus, a two-layer film having a sealant layer and a first intermediate layer having thicknesses of 10 μm and 20 μm, respectively, was obtained.
On the other hand, a two-component curable polyurethane anchor coating agent is applied to a biaxially stretched polyethylene terephthalate film (thickness: 16 μm) constituting the base material layer with a roll coater, and the application surface and the second layer film described above are applied. The molten m-LLDPE “Harmolex NH745” (manufactured by Nippon Polyethylene Co., Ltd.) constituting the second intermediate layer is extruded to a thickness of 10 μm between the surface of the first intermediate layer and the laminated film is formed by an extrusion lamination method. Obtained.
After the sealant layer side surface and the substrate layer side surface of this laminated film are corona-treated, a cationic antistatic agent “SAT-6C” (manufactured by Nippon Pure Chemical Co., Ltd.) is applied to both surfaces of the laminated film using a gravure coater. Thus, a cover film having a layer structure of base material layer / second intermediate layer / first intermediate layer / sealant layer was obtained.

(Examples 2-11, Comparative Examples 1-7)
A cover film was produced in the same manner as in Example 1 except that the resin composition and thickness described in Table 4 and Table 7 below were used.

(Example 12)
A two-layer film composed of an intermediate layer (first intermediate layer) / sealant layer was prepared in the same manner as in Example 1 except that the thickness of the first intermediate layer was 30 μm.
On the other hand, a two-component curable polyurethane anchor coating agent is applied to a biaxially stretched polyethylene terephthalate film (thickness 16 μm) constituting the base material layer with a roll coater, and the applied surface and the intermediate layer of the two-layer film described above. The side surface was laminated by a dry laminating method to obtain a laminated film. After the sealant layer side surface and the substrate layer side surface of this laminated film are corona-treated, a cationic antistatic agent “SAT-6C” (manufactured by Nippon Pure Chemical Co., Ltd.) is applied to both surfaces of the laminated film using a gravure coater. Thus, a cover film having a layer structure of base material layer / intermediate layer / sealant layer was obtained.

(Examples 13-18, Comparative Examples 8-11)
A cover film was produced in the same manner as in Example 12 except that the resins or resin compositions described in Table 5 and Table 8 below were used as raw materials for the intermediate layer or sealant layer.

(Example 19)
After applying a urethane anchor coating agent to the surface of the biaxially stretched polyethylene terephthalate film (thickness 25 μm) constituting the base material layer so that the dry thickness is about 1 μm, m-LLDPE “Harmolex NH745N constituting the intermediate layer” ”(Manufactured by Nippon Polyethylene Co., Ltd.) was extrusion coated with a T-die so as to have a thickness of 15 μm, thereby obtaining a two-layer film having a base layer / intermediate layer structure. Further, on the surface on the intermediate layer side of this two-layer film, as a resin constituting the sealant layer, 100 parts by mass of a hydrogenated resin “Tuftec H1041” (manufactured by Asahi Kasei Chemicals) of a triblock copolymer of styrene-butadiene-styrene, and A resin composition consisting of 25 parts by mass of an antiblocking agent master batch “PEX ABT-16” (manufactured by Tokyo Ink Co., Ltd.) was laminated by extrusion coating to a thickness of 20 μm to obtain a laminated film. After the corona treatment of the surface of the laminated film on the side of the sealant layer and the surface of the base material layer, a cationic antistatic agent “SAT-6C” (manufactured by Nippon Pure Chemical Co., Ltd.) is applied to both surfaces of the laminated film using a gravure coater. It was applied to obtain a cover film having a layer structure of base material layer / intermediate layer / sealant layer.

(Examples 20 to 23, Comparative Examples 12 to 16)
A cover film was produced in the same manner as in Example 19 except that the resin composition and thickness described in Table 6 and Table 9 below were used.

(Evaluation method)
Evaluation shown below was performed about the cover film produced in the said Examples 1-23 and Comparative Examples 1-16. These results are shown in Tables 4 to 9.
(1) Film-forming property The thickness of the formed cover film was measured at a total of 33 points of 11 points in the width direction (40 mm intervals) × 3 points in the flow direction (1 m intervals). The variation of was investigated. Thickness fluctuations of ± 20% or less were indicated as “good”, and thicknesses exceeding ± 20% were indicated as “bad”.

(2) Haze value The haze value was measured using an integrating sphere type measuring device according to the measuring method A of JIS K 7105: 1998. Those for which the film-forming property was remarkably bad and a film was not obtained were described as “not evaluated”.

(3) Heat seal property Using a taping machine “ST-60” (Systemation), seal head width 0.5 mm × 2, seal head length 32 mm, heat seal pressure 3.5 MPa, feed length 16 mm, heat seal time Heat seal a 5.5 mm wide cover film at 10 ° C. intervals from a seal iron temperature of 140 ° C. to 190 ° C. on an 8 mm wide polystyrene carrier tape (manufactured by Denki Kagaku Kogyo) in 0.2 seconds × twice (double seal) did. After leaving for 24 hours in an atmosphere with a temperature of 23 ° C. and a relative humidity of 50%, the cover film was peeled off at a speed of 300 mm / min and a peeling angle of 180 ° in an atmosphere with a temperature of 23 ° C. and a relative humidity of 50%. When the average peel strength when heat-sealed at a seal iron temperature of 190 ° C. and in the range of 0.3 to 0.9 N is “excellent” and heat-sealed at a seal iron temperature of either 140 ° C. or 190 ° C. Those having an average peel strength in the range of 0.3 to 0.9 N were designated as “good”, and those having an average peel strength outside this range were designated as “bad”. In addition, the film forming property was remarkably poor and the film was not obtained, was described as “not evaluated”.

(4) Difference between maximum value and minimum value of peel strength Using a taping machine “ST-60” (Systemation), seal head width 0.5 mm × 2, seal head length 32 mm, heat seal pressure 3.5 MPa, Cover tape of 5.5 mm width with 10 mm intervals from 160 ° C. to 190 ° C. with a feed length of 16 mm and a heat sealing time of 0.2 seconds × 2 times (double seal). (Industry company). Average when the cover film was peeled off at a temperature of 23 ° C. and a relative humidity of 50% for 24 hours and then peeled at a speed of 300 mm / min and a peeling angle of 180 ° in an atmosphere of a temperature of 23 ° C. and a relative humidity of 50%. The temperature of the heat seal iron was adjusted so that the peel strength was 0.4N. At this time, when the carrier tape 100 mm length is peeled, the difference between the maximum value and the minimum value of the peel strength is less than 0.2N as “excellent”, and the difference between 0.2N and less than 0.3N is “ “Non-defective” and 0.3N or higher were described as “bad”. In addition, the film forming property was remarkably poor and the film was not obtained, was described as “not evaluated”.

(5) Blocking property After heat-sealing so that the average peel strength is 0.4 N under the same conditions as in (4) above, the sealed carrier tape is wound on a 95 mm diameter paper tube with the cover film side facing outward. And left in an environment of 40 ° C. for 24 hours. At this time, the presence or absence of adhesion between the carrier tape and the cover film at places other than the heat-sealed portion was visually observed, and the case where no adhesion was observed was indicated as “good”, and the case where adhesion was observed was indicated as “bad”. In addition, the film forming property was remarkably poor and the film was not obtained, was described as “not evaluated”.

(6) Surface resistivity A resistivity meter “HIRESTA UP MCP-HT40” (Mitsubishi Chemical Corporation) is used in accordance with the method of JIS K6911 at an ambient temperature of 23 ° C., an ambient humidity of 50% (relative humidity), and an applied voltage of 500V. The surface resistivity of the sealant surface of the cover film was measured. In addition, the film forming property was remarkably poor and the film was not obtained, was described as “not evaluated”.

(7) Film cutting property The film cutting property was evaluated by the method shown in FIG.
First, using a taping machine “ST-60” (Systemation), seal head width 0.5 mm × 2, seal head length 32 mm, seal pressure 3.5 MPa, feed length 16 mm, seal time 0.5 seconds × 2 Electronic component made of polystyrene having a width of 24 mm and a cover film 1 having a width of 21.5 mm so that the average peel strength is 1.5 N and 2.0 N by adjusting the temperature of the seal head in a single cycle (double sealing). The carrier tape 103 was sealed.
Next, the carrier tape 103 with the cover film 1 sealed is cut out to a length of 550 mm as shown in FIG. 4 so that the bottom of the pocket of the carrier tape 103 is in contact with the vertical wall 101 to which the double-sided adhesive tape 102 is attached. Pasted. The cover film 1 was peeled 50 mm from the upper part of the affixed carrier tape 103, the tip of the peeled cover film 1 was sandwiched between clips 104, and a weight 106 having a mass of 1000 g was attached to the clip 104 via a string 105. After that, when the weight 106 was naturally dropped, “excellent” was obtained when the cover film 1 was not cut even with an average peel strength of 2.0 N, and “good” when the cover film 1 was not cut with an average peel strength of 1.5 N. In addition, a sample having an average peel strength of 1.5 N and observed to be cut was indicated as “bad”. In addition, the film forming property was remarkably poor and the film was not obtained, was described as “not evaluated”.

[Cover film having a layer structure of base material layer / intermediate layer / sealant layer / antistatic layer]
(Example 24)
80% by mass of an ethylene-methyl acrylate random copolymer resin “Elvalloy 1820AC” (Mitsui / DuPont Polychemical Co., Ltd.) and an antiblocking agent master batch “PEX ABT-16” (manufactured by Tokyo Ink Co., Ltd.) (that is, “Antiblocking Agent 1” ]) 20% by mass was blended with a tumbler to obtain a resin composition for a sealant layer.
Moreover, m-LLDPE “Harmolex NF464N” (manufactured by Nippon Polyethylene Co., Ltd.) was prepared as a resin constituting the intermediate layer.
These resins are individually extruded from a single screw extruder having a diameter of 40 mm, laminated with a multi-manifold die, the take-up speed is 15 m / min, the thickness of the sealant layer is 10 μm, and the thickness of the intermediate layer is 20 μm. A two-layer film (thickness: 30 μm) of a sealant layer / intermediate layer was produced.
On the other hand, a biaxially stretched polyethylene terephthalate film “E5100” (made by Toyobo Co., Ltd., thickness 16 μm) constituting the base material layer is coated with a urethane anchor coating agent so that the dry thickness is 2 μm, and the coated surface And a laminate film having a total thickness of 48 μm having a layer structure of base material layer / intermediate layer / sealant layer.
Subsequently, after applying a corona treatment to the surface of the sealant layer of the laminated film, the cationic polymer type antistatic agent “ASA-29CP” (manufactured by Takamatsu Yushi Co., Ltd.) 40 mass% (solid content) and an acrylic resin (methyl acrylate) / Methyl methacrylate copolymer resin emulsion “Viniblanc” (manufactured by Nissin Chemical Co., Ltd.) A water-based emulsion comprising 60% by mass (solid content) is applied by a gravure reverse method so that the thickness after drying is 0.4 μm. To form an antistatic layer, and a cover film having a layer structure of base layer / intermediate layer / sealant layer / antistatic layer was obtained.

(Examples 25-27)
A cover film was produced in the same manner as in Example 24 using the resins or resin compositions shown in Tables 1 to 3 at the compounding amounts shown in Table 10 below.

(Example 28)
80% by mass of ethylene-methyl acrylate random copolymer resin “Elvalloy 1820AC” (Mitsui / DuPont Polychemical Co., Ltd.) and 20% by mass of anti-blocking agent master batch “PEX ABT-16” (Tokyo Ink Co., Ltd.) To obtain a resin composition for the sealant layer.
On the other hand, m-LLDPE “Harmolex NF464N” (manufactured by Nippon Polyethylene Co., Ltd.) was prepared as a resin constituting the first intermediate layer.
Each of these resins is extruded from a single screw extruder having a diameter of 40 mm, laminated with a multi-manifold die, the take-up speed is 15 m / min, the thickness of the sealant layer is 10 μm, and the thickness of the first intermediate layer is 20 μm. A bilayer film having a thickness of 30 μm composed of a sealant layer / first intermediate layer was produced.
On the other hand, the biaxially stretched polyethylene terephthalate film “E5100” (made by Toyobo Co., Ltd., thickness 16 μm) constituting the base material layer is coated with a two-component curable polyurethane anchor coating agent with a roll coater, Extruded molten m-LLDPE “Harmolex NH745” (manufactured by Nippon Polyethylene Co., Ltd.) constituting the second intermediate layer to a thickness of 10 μm between the above-mentioned two-layer film and the first intermediate layer side surface, A laminated film having a total thickness of 56 μm having a layer structure of base layer / second intermediate layer / first intermediate layer / sealant layer was obtained by an extrusion lamination method.
Subsequently, after corona treatment was applied to the surface of the sealant layer, the cationic polymer antistatic agent “ASA-29CP” (manufactured by Takamatsu Yushi Co., Ltd.) 40 mass% (solid content) and an acrylic resin (methyl acrylate / methacrylic acid) A water-based emulsion composed of 60% by mass (solid content) of methyl copolymer resin emulsion “Vinibran” (manufactured by Nissin Chemical Co., Ltd.) was applied by a gravure reverse method so that the thickness after drying was 0.4 μm. An antistatic layer was formed to obtain a cover film having a layer structure of base material layer / second intermediate layer / first intermediate layer / sealant layer / antistatic layer.

(Examples 29 to 43)
A cover film was produced in the same manner as in Example 28 except that the resin composition and thickness described in Tables 10 to 12 below were used.

(Comparative Examples 17-19)
A cover film was produced in the same manner as in Example 24 except that the resin composition and thickness described in Table 13 below were used.

(Comparative Examples 20 to 34)
A cover film was produced in the same manner as in Example 28 except that the resin compositions and thicknesses described in Tables 13 to 15 below were used.

(Evaluation method)
Evaluation shown below was performed about the cover film produced in the said Examples 24-43 and Comparative Examples 17-34. These results are shown in Tables 10 to 15.
(1) Film-forming property The thickness of the formed cover film was measured at a total of 33 points of 11 points in the width direction (40 mm intervals) × 3 points in the flow direction (1 m intervals). The variation of was investigated. Thickness fluctuations of ± 10% or less were indicated as “excellent”, ± 20% or less as “good”, and those exceeding 20% as “bad”.

(2) Film cutting property The film cutting property was evaluated by the method shown in FIG.
First, using a taping machine “ST-60” (Systemation), seal head width 0.5 mm × 2, seal head length 32 mm, seal pressure 3.5 MPa, feed length 16 mm, seal time 0.5 seconds × 2 Electronic component made of polystyrene having a width of 24 mm and a cover film 1 having a width of 21.5 mm so that the average peel strength is 1.5 N and 2.0 N by adjusting the temperature of the seal head in a single cycle (double sealing). The carrier tape 103 was sealed.
Next, the carrier tape 103 with the cover film 1 sealed is cut out to a length of 550 mm as shown in FIG. 4 so that the bottom of the pocket of the carrier tape 103 is in contact with the vertical wall 101 to which the double-sided adhesive tape 102 is attached. Pasted. The cover film 1 was peeled 50 mm from the upper part of the affixed carrier tape 103, the tip of the peeled cover film 1 was sandwiched between clips 104, and a weight 106 having a mass of 1000 g was attached to the clip 104 via a string 105. After that, when the weight 106 was naturally dropped, “excellent” was obtained when the cover film 1 was not cut even with an average peel strength of 2.0 N, and “good” when the cover film 1 was not cut with an average peel strength of 1.5 N. In addition, a sample having an average peel strength of 1.5 N and observed to be cut was indicated as “bad”. In addition, the film forming property was remarkably poor and the film was not obtained, was described as “not evaluated”.

(3) Surface resistivity A resistivity meter “HIRESTA UP MCP-HT40” (Mitsubishi Chemical Corporation) is used according to the method of JIS K6911 at an ambient temperature of 23 ° C., an ambient humidity of 50% (relative humidity), and an applied voltage of 500V. The surface resistivity of the sealant surface of the cover film was measured. In addition, the film forming property was remarkably poor and the film was not obtained, was described as “not evaluated”.

(4) Total light transmittance and (5) Haze value The total light transmittance and haze value were measured using an integrating sphere measuring device according to measurement method A according to JIS K 7105: 1998. Those for which the film-forming property was remarkably bad and a film was not obtained were described as “not evaluated”. If the cover film has a haze value of 50% or more, it may be difficult to confirm the contents in the process of inspecting whether the contents are correctly inserted after packaging the electronic parts with the cover film.

(6) Sealing performance Using a taping machine “ST-60” (Systemation), seal head width 0.5 mm × 2, seal head length 32 mm, seal pressure 3.5 MPa, feed length 16 mm, seal time 0.2 The cover film having a width of 21.5 mm was heat-sealed on a polystyrene carrier tape having a width of 24 mm (manufactured by Denki Kagaku Kogyo Co., Ltd.) at intervals of 10 ° C. from a sealing iron temperature of 140 ° C. to 180 ° C. in 2 seconds × double sealing. After leaving for 24 hours in an atmosphere with a temperature of 23 ° C. and a relative humidity of 50%, the cover film was peeled off at a speed of 300 mm / min and a peeling angle of 180 ° in an atmosphere with a temperature of 23 ° C. and a relative humidity of 50%. The average peel strength when heat-sealed at a seal iron temperature of ˜180 ° C. is “excellent” when the average peel strength is in the range of 0.3-0.8 N, and the average peel when heat-sealed at a seal iron temperature of 140 ° C.-180 ° C. Those having a strength in the range of 0.2 to 1.0 N were designated as “good”, and those having an average peel strength outside this range were designated as “bad”. In addition, the film forming property was remarkably poor and the film was not obtained, was described as “not evaluated”.

(7) Stability over time of peel strength Using a taping machine “ST-60” (Systemation), seal head width 0.5 mm × 2, seal head length 32 mm, seal pressure 3.5 MPa, feed length 16 mm, seal By adjusting the seal head temperature at a time of 0.2 seconds x 2 times (double sealing), the sample is left for 24 hours in an atmosphere at a temperature of 23 ° C and a relative humidity of 50%, and then the temperature is also 23 ° C and the relative humidity is 50%. A 21.5 mm wide carrier film with a 24 mm wide polystyrene carrier tape so that the average peel strength when peeling the cover film at a speed of 300 mm per minute and a peel angle of 180 ° in an atmosphere of 0.4N is 0.4N. It was heat-sealed (manufactured by Denki Kagaku Kogyo). As an accelerated environment test, this was stored for 7 days in a high-temperature and high-humidity environment at 52 ° C. and 95% relative humidity, and then left for 24 hours in an environment at 23 ° C. and 50% relative humidity, and then peel strength was measured. . A change in average peel strength after storage in a high-temperature and high-humidity environment was indicated as excellent, 0.2N or less as good, 0.3N or less as good, and other than the above as bad. In addition, the film forming property was remarkably poor and the film was not obtained, was described as “not evaluated”.

(8) Blocking property Using a taping machine “ST-60” (Systemation), seal head width 0.5 mm × 2, seal head length 32 mm, seal pressure 3.5 MPa, feed length 16 mm, seal time 0.2 By adjusting the seal head temperature in 2 seconds x 2 (double seal), left in an atmosphere of 23 ° C and 50% relative humidity for 24 hours, and then in an atmosphere of 23 ° C and 50% relative humidity. In order to obtain an average peel strength of 0.4 N when the cover film is peeled off at a speed of 300 mm per minute at a peel angle of 180 °, a 21.5 mm wide cover film is made of a 24 mm wide polystyrene carrier tape (Electrochemical Industry). Heat-sealed.
Next, the sealed carrier tape is wound around a paper tube having a diameter of 95 mm so that the cover film side faces outside, and then left in a 60 ° C. environment for 3 days and 7 days. The presence or absence of adhesion was visually observed. Those that showed adhesion when left in an environment of 60 ° C. for 3 days are indicated as “bad”. No adhesion was observed when left for 3 days, and adhesion was seen when left for 7 days. Was marked as “good” and those that did not show adhesion even after being left for 7 days were marked as “excellent”. In addition, the film forming property was remarkably poor and the film was not obtained, was described as “not evaluated”.

  In the above, this invention was demonstrated based on the Example. It is to be understood by those skilled in the art that this embodiment is merely an example, and that various modifications are possible and that such modifications are within the scope of the present invention.

Claims (7)

A base material layer;
An intermediate layer comprising a resin composition comprising a density 0.900~0.940 × ^{10 3} kg / ^m 3 of metallocene linear low density polyethylene resin 50% by weight or more,
A sealant layer comprising an ethylene-based copolymer resin comprising an olefin component from 50 to 85 wt%, the ethylene copolymer resin is an ethylene - acrylic acid ester random copolymer resin, an ethylene - methacrylic acid ester random copolymer resin A sealant layer that is at least one selected from the group consisting of a hydrogenated styrene-butadiene-styrene block copolymer, and a hydrogenated styrene-isoprene-styrene block copolymer;
Formed on the surface of the sealant layer side, the formula (I):

(I)
(In the formula, A represents an oxygen atom or an imino group, R ₁ represents a hydrogen atom or a methyl group, and R ₂ , R ₃ and R ₄ may be the same or different, each having 1 to 18 carbon atoms. R ₅ represents an alkylene group having 1 to 4 carbon atoms, X ⁻ represents an anion, and m represents an integer in the range of 1 to 5000)
And an antistatic layer containing a resin composition in which a cationic polymer type antistatic agent having a quaternary ammonium salt shown in the side chain is dispersed in an acrylic resin. Cover film heat-sealed to carrier tape. Ethylene copolymer resin contained in the sealant layer, of ethylene - cover film according to claim 1 Ru acrylate random copolymer resin der. The cover film according to claim 1 or 2, wherein the sealant layer contains 5 to 30% by mass of organic fine particles or inorganic fine particles. Cover film according to the substrate layer, any one of claims 1 comprising the resin composition 3 comprising a biaxially oriented polyethylene terephthalate or biaxially oriented polyethylene terephthalate. The ratio of the cationic polymer type antistatic agent to the acrylic resin in the resin composition contained in the antistatic layer is 20 to 60% by mass of the cationic polymer type antistatic agent and 40 to 80% by mass of the acrylic resin. The cover film according to any one of claims 1 to 4, wherein: The cover film according to any one of claims 1 to 5, wherein the antistatic layer contains 10 to 50% by mass of organic fine particles or inorganic fine particles. The electronic component package which heat-sealed the cover film as described in any one of Claim 1 to the embossed carrier tape which accommodated the electronic component.

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